When Judge Neil Gorsuch arrives on Capitol Hill on Monday morning to begin his confirmation hearings for a seat on the Supreme Court, he will give President Trump his first chance to make a lasting imprint on the federal judiciary — and Republicans a fresh test to work their will now that they control all of Washington’s levers of power.

Gorsuch, a federal appeals court judge from Colorado, was promoted by conservative legal activists because of his sterling credentials, a decade of right-of-center rulings and his allegiance to the same brand of constitutional interpretation employed by the late justice he would replace, Antonin Scalia.

“Single best thing the president’s done,” said Sen. Lindsey O. Graham (R-S.C.), a frequent Trump foil who predicted Republican unity on the matter and an easy victory for the president following the string of controversies that Trump has wrought since he took office.

All of that also sets up a stark dilemma for Senate Democrats. Monday brings their newest opportunity since the confirmation hearings of Trump’s Cabinet to take a stand against a young administration that has horrified liberal Americans with efforts to strip away provisions of the Affordable Care Act, impose an entry ban on some immigrants and deeply cut federal agencies’ budgets.

The left also remains angry about a Supreme Court seat that has been vacant since Scalia died 13 months ago, after which Senate Majority Leader Mitch McConnell (R-Ky.) decided to block a hearing for President Barack Obama’s selection for the seat, Judge Merrick Garland of the U.S. Court of Appeals for the D.C. Circuit.

Gorsuch seemed to forecast what might await him from Democrats in a 2002 column he wrote lamenting the state of the Supreme Court nomination process: “When a favored candidate is voted down for lack of sufficient political sympathy to those in control, grudges are held for years, and retaliation is guaranteed.”

Yet Democrats are divided about how to take on a genial jurist who has made few waves in the weeks since Trump nominated him and he began meeting with lawmakers on Capitol Hill.

Gorsuch “is a bit of a puzzle,” said Sen. Dianne Feinstein (Calif.), the top Democrat on the Senate Judiciary Committee. “We’re going to try to put those pieces together so that the puzzle is complete and we have an understanding of what kind of a fifth vote will be going on the court.”

Asked about what more she hopes to learn about Gorsuch’s stances, Feinstein said: “Voting rights. Right to choose. Guns. Corporate dollars in elections. Worker safety. Ability of federal agencies to regulate. All of the environmental issues — water, air.”

Senators and their staffsare also examining Gorsuch’s role as a high-ranking official in the Justice Department at the time the George W. Bush administration was dealing with Guantanamo Bay detainees, reports of torture and anti-terrorism policies.

A new trove of materials released this weekend shows Gorsuch playing a central role in coordinating legal and legislative strategy, but portraying himself as reconciling the many opinions of those in the administration rather than driving policy.

“I am but the scrivener looking for language that might please everybody,” he wrote in one email.

(Peter Stevenson,Gillian Brockell/The Washington Post)

Four days of hearings are set to begin Monday, when Gorsuch will sit and listen for several hours as members of the Judiciary Committee read opening statements. He is poised to deliver his opening statement on Monday afternoon, giving senators and the nation an early indication of how he might serve on the court.

On Tuesday and Wednesday, Gorsuch is set to face at least 50 minutes of questioning by each member of the panel. The proceedings are expected to conclude Thursday with a panel of witnesses speaking for or against Gorsuch.

Some of the issues that normally animate Supreme Court confirmation hearings won’t depend upon Gorsuch. Decisions from last term showed there was still support on the court for limited affirmative action in higher education, for instance. The majority that found a constitutional right for same-sex couples to marry remains. And whatever Gorsuch’s position on abortion rights, Justice Anthony M. Kennedy’s vote to strike down a Texas law last year reaffirmed the court’s rulings that say government may not pass restrictions that unduly burden a woman’s right to an abortion.

But Gorsuch would probably reinforce the court’s pro-business image and skepticism about some significant environmental programs begun under Obama. His past decisions show him to be extremely protective of the rights of those who object to even generally applicable government laws and regulations that they say violate their religious beliefs.

If Gorsuch is approved in time for the court’s April hearings, he could play a significant role in a separation-of-powers case in which a church complains it was illegally denied a state grant. A conservative movement to curb the power of labor unions — stalled last year by Scalia’s death — is sure to resume. Cases involving legal protections for gay and transgender people are likely to arrive at the court soon.

Beyond their questions about Gorsuch’s record, Democrats plan to use his confirmation hearing to question the overall direction of Chief Justice John G. Roberts Jr.’s court.

“When I hear my Republican colleagues say, ‘We want another judge like Scalia, who isn’t an activist,’ I say, ‘What are you talking about? This has been an incredibly activist court,’ ” said Sen. Al Franken (D-Minn.), a member of the Judiciary Committee. “So I want to ask him” about that.

The future of the court was a significant factor in Trump winning over conservative voters who might otherwise have been uncomfortable with the candidate’s ideology, values and personal history.

“Even if people don’t like me, they have to vote for me,” Trump said at a rally in Virginia last year. “You know why? Justices of the Supreme Court.”

In November exit polls, more than 1 in 5 voters said that Supreme Court appointments were “the most important factor” in determining their choice; of those voters, 56 percent went to Trump.

Sen. Ted Cruz (Tex.), Trump’s final Republican opponent in last year’s presidential campaign, described the Gorsuch pick as “the most transparent Supreme Court selection process in modern times” because Trump drew Gorsuch from a list of 21 candidates supplied to him by conservative legal groups during the campaign.

Gorsuch’s nomination “is not the product just of ordinary Washington political decision-making but rather a presidential election decided by the American people,” Cruz said.

Not a single Democrat, meanwhile, has pledged support for Gorsuch. That is partly fueled by a liberal base agitating for a win since Trump was inaugurated on Jan. 20. Unable to block the large majority of Trump’s executive branch nominations, some Democrats want to draw blood and force Gorsuch to clear procedural hurdles that require 60 senators to vote in his favor. Republicans have only 52 members in the upper chamber, so they would need eight Democrats to cross the aisle and vote with them.

Mounting a filibuster to force such a vote could amount to a declaration of war against Republicans that some Democrats, particularly those from conservative states that voted for Trump last year, may be unwilling to do.

“The reality is that there is political pressure on them,” Caroline Fredrickson, president of the liberal American Constitution Society, said of Democrats. The Supreme Court is different from other choices Trump will make, she said, because “this is forever, or at least for the rest of my lifetime.”

Democrats have expressed specific concern about Gorsuch’s record of independence following Trump’s criticism of the judiciary, including his remark about the “so-called judge” who struck down his first entry ban. Afterward, Gorsuch called Trump’s attacks on the courts “demoralizing.”

Senate Minority Leader Charles E. Schumer (D-N.Y.) said Republicans should expect Democrats to question Gorsuch aggressively because “we’re in a new world” in which Trump is pushing the limits of his constitutional authority. Knowing where Gorsuch stands on that issue is critical, he said.

“I have deep, deep doubts about him and his judicial demeanor, and the fact that he appears to be a calm, erudite person is not the key issue here,” Schumer said. “There are lot of people like that. It’s what goes into how he decides cases.”

Sen. Richard J. Durbin (D-Ill.) said he will ask Gorsuch to weigh in on Trump’s push to implement an entry ban on visitors from certain majority-Muslim countries, because “the Supreme Court in the near future will be tested on constitutional questions involving separation of powers.”

Franken and Sen. Amy Klobuchar (D-Minn.) said they want to press Gorsuch on his cases involving campaign finance law, while Franken said he will also focus on Gorsuch’s record on voting rights and women’s reproductive rights. Sen. Patrick J. Leahy (D-Vt.) said he plans to use documents provided by the Justice Department to ask Gorsuch about his years working for Bush on such matters as executive authority and the interrogation of terrorism suspects.

Gorsuch “is going to have to establish very much that he’d be independent of any president and that he’s going to uphold the rights of all Americans,” Leahy said. “He’s got a lot of work to do in that regard.”

Many conservative activists and GOP lawmakers say that the laundry list of Democratic concerns is evidence that they don’t quite know how to pin down Gorsuch.

Questions about Gorsuch’s potential independence from the Trump White House or conservative causes will be “an exercise in self-contradiction for the Democrats,” said Leonard Leo, who has been advising Trump on judicial matters and is on leave from his role as executive vice president of the conservative Federalist Society, which helped advise Trump on his list of potential court nominees.

“They want Judge Gorsuch to say, ‘I’m my own man, I’m independent, I’m going to evaluate the actions of the executive branch on their own merits without regards to the president or any political issue,’ ” he said. “And then 10 minutes later they’re going to ask him to promise how he’s going to rule on Roe v. Wade and every other case that comes before the court.”

“There’ll be an effort to use him as a piñata to jam the president,” Leo said, later adding that such attempts would be “unfortunate and inappropriate.”

And there could be other issues to emerge. With only eight members and the threat of ideological deadlock, the court has seemed reluctant to accept some controversial cases.

Gorsuch’s nomination to replace Scalia, with whom he shares an “originalist” philosophy of constitutional interpretation, is in some ways like other recent replacements — by some measures a zero sum, ideologically speaking. Bush’s two nominees, Roberts and Samuel A. Alito Jr., also replaced Republican nominees. Obama’s choices of Sonia Sotomayor and Elena Kagan took the places of liberals.

But justices’ ideologies are not predictable purely by virtue of the party of the president who nominated them. Alito’s replacement of the more moderate Sandra Day O’Connor moved the court to the right on several issues, including abortion, voting rights and campaign finance law.

“I don’t accept the premise that it’s ‘Scalia’s seat,’ ” Durbin said. “I don’t know what the next seat will be or when it will be, so I take each of them seriously.”

Watching how Gorsuch fares will be the eight current members of the high court, who have said very little publicly in the past year about their diminished ranks.

Weeks before Scalia’s death, Roberts told an audience in Boston that public skepticism concerning the court starts with the Senate confirmation process. Decades ago, two of the court’s most controversial justices — Scalia on the right and Ruth Bader Ginsburg on the left — were confirmed practically unanimously, he said.

But the three “extremely well-qualified” nominees who followed Roberts — Alito, Sotomayor and Kagan — were approved largely on party-line votes.

“That suggests to me that the process is being used for something other than ensuring the qualifications of the nominees,” Roberts said.

Skittish Republicans acknowledged that Trump could still spoil Gorsuch’s chances. Graham said it could happen “if the president tweets any more about judges.”

Said Sen. John Cornyn (R-Tex.), the chamber’s second-ranking Republican: “I think the best thing the White House could do is just let the Senate do its work.”